• Imaging Science in Dentistry
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• v.31 no.2
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• pp.117-120
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• 2001

A 66-year-old man visited author's institute complaining of the swelling on the submandibular gland area. Clinically, the exophytic mass penetrated the skin of the submandibular area. On MRI, the lesion occupied the left submandibular space and extended downward, protruding exterior to the subcutaneous fat layer, but the center of the lesion was located on the side of the skin and the growth exterior to the skin was prominent. Demarcation of the lesion and the submandibular gland was unclear. Histopathologically the epithelial nests and keratin production were seen, then the biopsy result was squamous cell carcinoma. The stroma of lesion showed a myxoid characteristic and some ducts showed metaplasia of the ductal cells, which suggested the gland-origin carcinoma. However, lots of keratin production and carcinomatous change of cells continuous to the normal epithelium of the skin, the skin-origin carcinoma invading into the submandibular gland area could not be excluded.

• Journal of Oral Medicine and Pain
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• v.41 no.2
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• pp.72-75
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• 2016

Lichen planus is a chronic disease characterized by bilateral and multiple lesions on the skin or oral mucosa. Lichen planus is caused by immune mediated degeneration along the border between epithelium and connective tissue. The incidence of oral squamous cell carcinoma in patients diagnosed with oral lichen planus (OLP) is reported to be between 0.4%-5.6% in different studies and the World Health Organization has categorized lichen planus as "a potentially malignant disorder". However, the correlation between OLP and oral cancer still remains controversial as some reported that the reason for increased incidence of squamous cell carcinoma in OLP patient is misdiagnosis of dysplastic lesion as OLP. This report aims to discuss the correlation between OLP and oral cancer through a case of middle aged woman diagnosed with OLP who was successfully treated but developed squamous cell carcinoma 8 years later.

• Journal of Periodontal and Implant Science
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• v.49 no.5
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• pp.270-286
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• 2019

Purpose: Despite the well-known anti-inflammatory effects of vitamin D in periodontal health, its mechanism has not been fully elucidated. In the present study, the effect of vitamin D on strengthening E-cadherin junctions (ECJs) was explored in human gingival keratinocytes (HGKs). ECJs are the major type of intercellular junction within the junctional epithelium, where loose intercellular junctions develop and microbial invasion primarily occurs. Methods: HOK-16B cells, an immortalized normal human gingival cell line, were used for the study. To mimic the inflammatory environment, cells were treated with tumor necrosis factor-alpha ($TNF-{\alpha}$). Matrix metalloproteinases (MMPs) in the culture medium were assessed by an MMP antibody microarray and gelatin zymography. The expression of various molecules was investigated using western blotting. The extent of ECJ development was evaluated by comparing the average relative extent of the ECJs around the periphery of each cell after immunocytochemical E-cadherin staining. Vitamin D receptor (VDR) expression was examined via immunohistochemical analysis. Results: $TNF-{\alpha}$ downregulated the development of the ECJs of the HGKs. Dissociation of the ECJs by $TNF-{\alpha}$ was accompanied by the upregulation of MMP-9 production and suppressed by a specific MMP-9 inhibitor, Bay 11-7082. Exogenous MMP-9 decreased the development of ECJs. Vitamin D reduced the production of MMP-9 and attenuated the breakdown of ECJs in the HGKs treated with $TNF-{\alpha}$. In addition, vitamin D downregulated $TNF-{\alpha}$-induced nuclear factor kappa B ($NF-{\kappa}B$) signaling in the HGKs. VDR was expressed in the gingival epithelium, including the junctional epithelium. Conclusions: These results suggest that vitamin D may avert $TNF-{\alpha}$-induced downregulation of the development of ECJs in HGKs by decreasing the production of MMP-9, which was upregulated by $TNF-{\alpha}$. Vitamin D may reinforce ECJs by downregulating $NF-{\kappa}B$ signaling, which is upregulated by $TNF-{\alpha}$. Strengthening the epithelial barrier may be a way for vitamin D to protect the periodontium from bacterial invasion.

• Journal of Korean Dental Science
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• v.9 no.1
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• pp.9-18
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• 2016

Purpose: Wnt signaling plays an essential role in the dental epithelium and mesenchyme during tooth morphogenesis. Deletion of the Wntless (Wls) gene in odontoblasts appears to reduce canonical Wnt activity, leading to inhibition of odontoblast maturation. However, it remains unclear if autonomous Wnt ligands are necessary for differentiation of dental pulp cells into odontoblast-like cells to induce reparative dentinogenesis, one of well-known feature of pulp repair to form tertiary dentin. Materials and Methods: To analyze the autonomous role of Wls for differentiation of dental pulp cells into odontoblast-like cells, we used primary dental pulp cells from unerupted molars of Wls-floxed allele mouse after infection with adenovirus for Cre recombinase expression to knockout the floxed Wls gene or control GFP expression. The differentiation of dental pulp cells into odontoblast-like cells was analyzed by quantitative real-time polymerase chain reaction. Result: Proliferation rate was significantly decreased in dental pulp cells with Cre expression for Wls knockout. The expression levels of Osterix (Osx), runt-related transcription factor 2 (Runx2), and nuclear factor I-C (Nfic) were all significantly decreased by 0.3-fold, 0.2-fold, and 0.3-fold respectively in dental pulp cells with Wls knockout. In addition, the expression levels of Bsp, Col1a1, Opn, and Alpl were significantly decreased by 0.7-fold, 0.3-fold, 0.8-fold, and 0.6-fold respectively in dental pulp cells with Wls knockout. Conclusion: Wnt ligands produced autonomously are necessary for proper proliferation and odontoblastic differentiation of mouse dental pulp cells toward further tertiary dentinogenesis.

• The Journal of Korean Academy of Prosthodontics
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• v.37 no.6
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• pp.717-729
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• 1999

Although many studies on the cytotoxicity of the dental cast base metal alloys and their components have been carried out, the results are rather conflicting because of the different type of cells used and the various experimental procedures taken. Recently a number of scientists have claimed that it would be preferable to focus on the use of cells from relevant specific location of the human bodies. Consequently, the primary cultured oral keratinocyte derived from oral mucous along with nickel chloride and several of widely used dental cast base metal alloys(two Ni-Cr alloys and one Co-Cr alloy)in domestic were selected for this study, from which 1) The amounts of released metal ions were determined using atomic absorption spectrometry, 2) The cytotoxicity of nickel chloride and dental cast base metal alloys was evaluated via MTT assay, and finally, 3) The amounts of released metal ions and the cytotoxicity of nickel chloride were correlated with the cytotoxicity of dental cast base metal alloys And, the results were summarized as follows; 1. Nickel ion from Ni-Cr alloys and Cobalt ion from Co-Cr alloys resulted in maximum releasing rate during first 2h hours, followed by a decrease in releasing rate with time. Chromium ion were found to be minimal in all alloys. 2. In cytotoxic test. with $40{\mu}M,\;80{\mu}M$ of nickel chloride, there were observed an increase in the relative cell number compared to control samples after 24 hours. With $160{\mu}M$, there was found to be no difference in the relative cell number with control, except that 48 hour showed a increase in relative cell number. With $320{\mu}M$, the relative cell number remained constant and decreased after 48 hours, and with $640{\mu}M$, a continuing decrease in relative cell number was observed throughout test period. 3 The sensitivity of primary cultured oral epithelium to nickel was lower compared to the cells used in other studies. 4. CB-80 Soft and Regalloy showed no cytotoxicity to primary cultured oral epithelium and New crown resulted in a slight cytotoxicity. In conclusion, it was shown that the primary cultured oral keratinocytes could be applied successfully as testing cells in cytotoxicity test. Futhermore, the dental cast base metal alloys used in this study were found to be biocompatible.

• International Journal of Oral Biology
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• v.36 no.1
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• pp.31-35
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• 2011

Teeth develop via a reciprocal induction between the ectomesenchyme originating from the neural crest and the ectodermal epithelium. During complete formation of the tooth morphology and structure, many cells proliferate, differentiate, and can be replaced with other structures. Apoptosis is a type of genetically-controlled cell death and a biological process arising at the cellular level during development. To determine if apoptosis is an effective mechanism for eliminating cells during tooth development, this process was examined in the rat mandible including the developing molar teeth using the transferase-mediated dUTP-biotin nick labeling (TUNEL) method. The tooth germ of the mandibular first molar in the postnatal rat showed a variety of morphological appearances from the bell stage to the crown stage. Strong TUNEL-positive reactivity was observed in the ameloblasts and cells of the stellate reticulum. Odontoblasts near the prospective cusp area also showed a TUNEL positive reaction and several cells in the dental papilla, which are the forming pulp, were also stained intensively in this assay. Our results thus show that apoptosis may take place not only in epithelial-derived dental organs but also in the mesenchyme-derived dental papilla. Hence, apoptosis may be an essential biological process in tooth development.

• Maxillofacial Plastic and Reconstructive Surgery
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• v.33 no.6
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• pp.535-539
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• 2011

Epidermoid cyst is a cystic form of teratoma and believed to be derived from trapped embryonic cells along the lines of embryonic closure. A 28-year-old woman presented with a painless swelling over the left mandibular area. On panoramic view, the mandible revealed a $5.5{\times}2.0\;cm^2$ multilocular radiolucent lesion of the left mandibular body and a computed tomography scan showed expansion of both the buccal and lingual plates in the same area. Microscopy found stratified squamous epithelium of the cystic wall and cystic contents of keratinized material. The histological diagnosis wasan epidermoid cyst. The most common location of epidermoid cyst at the head and neck is in the orbit (47%), followed by the mouth floor (23%) and the cervical area (9~24%), but in the jaw bone, it is considered very infrequent. We report the uncommon epidermoid cyst in the mandibular body that had a good healing outcome after treatment with a conservative marsupialization during the 40 months follow-up.

• Journal of Oral Medicine and Pain
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• v.40 no.2
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• pp.79-81
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• 2015

Oral hairy leukoplakia occurs on the lateral surface of the tongue that clinically as an asymptomatic white lesion. It is mainly found in patient with human immunodeficiency virus infection. However, it rarely outbreak immunosuppressed patients after organ transplantation, or the patients taking steroids or immunosuppressants. It is the result of proliferating Epstein-Barr virus in the oral epithelium. Most of human immunodeficiency virus infected patients with oral hairy leukoplakia are highly contagious and possible to progress acquired immunodeficiency syndrome. Therefore, the early diagnosis of oral hairy leukoplakia is very important. Taking a thorough history and human immunodeficiency virus screening test is highly recommended in case oral hairy leukoplakia is detected. In this case, a 29-year-old man presented with whitish lesion on lateral border of tongue is diagnosed as oral hairy leukoplakia and human immunodeficiency virus infection.

• International Journal of Oral Biology
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• v.46 no.1
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• pp.39-44
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• 2021

This study aimed to investigate whether neurotransmitter receptors in the nervous system were also expressed in oral keratinocytes. Expressions of various neurotransmitter receptor genes in immortalized mouse oral keratinocyte (IMOK) cells were examined by reverse transcriptase polymerase chain reaction. IMOK cells expressed calcitonin gene-related peptide (CGRP) receptor subunit genes Ramp1 and Ramp3 and glutamate receptor subunit genes Grina, Gria3, Grin1, Grin2a, and Grin2d. Moreover, IMOK cells expressed Adrb2 and Chrna5 that encode beta 2 adrenergic receptor and cholinergic receptor nicotinic alpha 5 for sympathetic and parasympathetic neurotransmitters, respectively. The expression of Bdkrb1 and Ptger4, which encode receptors for bradykinin and prostaglandin E2 involved in inflammatory responses, was also observed at low levels. Expressions of Ramp1 and Grina in the mouse gingival epithelium were also confirmed by immunohistochemistry. When the function of neurotransmitter receptors expressed on IMOK cells was tested by intracellular calcium response, CGRP, glutamate, and cholinergic receptors did not respond to their agonists, but the bradykinin receptor responded to bradykinin. Collectively, oral keratinocytes express several neurotransmitter receptors, suggesting the potential regulation of oral epithelial homeostasis by the nervous system.

• Maxillofacial Plastic and Reconstructive Surgery
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• v.22 no.4
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• pp.442-448
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• 2000

Developmental anomalies arising from the branchial apparatus include cysts, external sinuses, internal sinuses, and complete fistulas. Second branchial cleft cysts are by far the most common among these anomalies. It may occur at any age, being most common in the third decade, and more frequent in the male than in the female. It usually presents a smooth, round, nontender fluctuant mass located between the level of the tragus and the clavicle along the anteromedial border of the sternocleidomastoid muscle. It is lined by respiratory or squamous epithelium unless inflammation is present. The considerable amount of lymphoid tissue may be found beneath the epithelium. The treatment of choice of branchial cleft cyst is surgical excision. If the lesion is acutely infected, however, it is essential to relieve the infection prior to the surgery. This report deals with two cases of second branchial cleft cyst. In case 1, the cyst had rapidly increased in size over pregnant period. In case 2, the patient presented the swelling in the left neck, and had the history of incision and drainage because of misdiagnosis as submandibular space abscess. The infection was treated by antibiotic therapy in the first place, and then complete surgical excision was made. There was no evidence of any recurrence or complications for these $3{\sim}4$ years.